torque sensor

Abstract

An embodiment of the present application provides a torque sensor which is high in rigidity, thin, and light in weight. A first structure (11) is annular and has a first outer diameter and a first inner diameter. A second structure (12) is annular, disposed separately from the first structure on an axis of the first structure, and has a second outer diameter smaller than the first inner diameter and a second inner diameter. A plurality of third structures (13) are connected between the first structure and the second structure, and have at least a thickness of a distance or more in an axial direction between the first structure and the second structure and a width wider than a distance between the first structure and the second structure in a direction orthogonal to the axis. A plurality of strain sensors (14) are connected between the first structure and the second structure and disposed at right angles with respect to the axis.

Description

Technical Field

[0001] Embodiments of the present invention relate to, for example, torque sensors applied to joints of robotic arms. Background Technology

[0002] When the joints of a robotic arm (hereinafter referred to as the arm) have low rigidity, it is difficult to determine the position of the arm's tip due to inertia during arm movements. Therefore, the joints of the arm need to have high rigidity.

[0003] In addition, the torque sensor is positioned at the joint of the arm. Therefore, in order to improve the accuracy of torque detection, the torque sensor needs to have high rigidity in the torque direction and in other torque directions.

[0004] Typically, for example, in the case of a torque sensor having multiple beams disposed between two annular elastic bodies having the same diameter, the stiffness in the torque and moment directions can be improved by optimizing the length and number of the multiple beams. In this case, weight reduction can be achieved by increasing the opening area of ​​the two annular elastic bodies. However, since the two elastic bodies are connected by multiple beams arranged axially, the thickness of the torque sensor increases, making it difficult to make the torque sensor thinner (see, for example, Patent Document 1: Japanese Patent Application Publication No. 2010-169586).

[0005] On the other hand, in the case of a torque sensor having two concentrically arranged annular elastomers of different diameters and multiple beams radially arranged between these elastomers, the thickness of the beams (the thickness along the axial direction of the elastomers) can be set to be equal to or less than the axial thickness of the two elastomers. Therefore, a thin torque sensor capable of high-precision detection can be realized. However, in this case, to obtain the required rigidity, the two elastomers need to be sufficiently thick, increasing the weight of the torque sensor (see, for example, Patent Document 2: Japanese Patent Application Publication No. 2021-060349, Patent Document 3: Japanese Patent Application Publication No. 2017-172983, and Patent Document 4: Japanese Patent No. 6648340).

[0006] Therefore, while increasing the rigidity of the torque sensor, the thickness and weight of the torque sensor increase, leading to a larger size. Summary of the Invention

[0007] The technical problem that the invention aims to solve The embodiments of the present invention provide a torque sensor that is highly rigid, thin, and lightweight.

[0008] Technical solutions for solving technical problems The torque sensor of this embodiment includes: an annular first structure having a first outer diameter and a first inner diameter; an annular second structure disposed separately from the first structure on the axis of the first structure, having a second outer diameter and a second inner diameter smaller than the first inner diameter; a plurality of third structures connected between the first structure and the second structure, having a thickness at least greater than the axial distance between the first structure and the second structure, and a width in a direction orthogonal to the axis that is wider than the distance between the first structure and the second structure; and a plurality of strain sensors connected between the first structure and the second structure and disposed perpendicular to the axis. Attached Figure Description

[0009] Figure 1 This is a perspective view showing the torque sensor according to the first embodiment.

[0010] Figure 2 It is shown Figure 1 The top view of the surface of the torque sensor is shown.

[0011] Figure 3 yes Figure 1 The torque sensor shown is a side view.

[0012] Figure 4 It is shown Figure 1 The top view of the back of the torque sensor is shown.

[0013] Figure 5 It is along Figure 1 The image shows a cross-sectional view of the torque sensor along the V-V line.

[0014] Figure 6 It shows that Figure 1 The figure shown is a perspective view of the torque sensor after it has been removed as the third structural element of the beam.

[0015] Figure 7 This is a perspective view showing a first variant of the third structure.

[0016] Figure 8 It is a diagram showing the relationship between the angle of the third structure and the displacement, mass, and stress relative to the torque.

[0017] Figure 9A This is a schematic diagram illustrating an example of mounting a torque sensor of the first embodiment onto a robotic arm.

[0018] Figure 9B This is a schematic diagram illustrating an example of mounting an existing torque sensor onto a robotic arm.

[0019] Figure 10This is a graph showing a comparison of the axial displacement of the torque sensor of the first embodiment relative to height with that of a conventional example.

[0020] Figure 11 This is a perspective view showing the second variation of the third structure.

[0021] Figure 12 This is a perspective view showing the third variation of the third structure.

[0022] Figure 13 This is a side view showing the fourth variation of the third structure.

[0023] Figure 14 This is a side view showing the fifth variation of the third structure.

[0024] Figure 15 This is a side view showing the sixth variation of the third structure.

[0025] Figure 16 This is a side view showing the seventh variation of the third structure.

[0026] Figure 17 This is a diagram showing the relationship between stress and stiffness relative to moment for various variations of the third structure.

[0027] Figure 18 This is a top view showing the surface of the torque sensor according to the second embodiment.

[0028] Figure 19 It is shown Figure 18 The torque sensor shown is a side view.

[0029] Figure 20 This is a top view showing the rear of the torque sensor according to the third embodiment.

[0030] Figure 21 yes Figure 20 The torque sensor shown is a side view.

[0031] Figure 22 This is a perspective view showing the torque sensor according to the fourth embodiment. Detailed Implementation

[0032] The embodiments will now be described with reference to the accompanying drawings. In the drawings, the same parts are given the same reference numerals.

[0033] (First Implementation) Figures 1 to 5 A torque sensor 10 according to a first embodiment is shown. The torque sensor 10 includes: a ring-shaped first structure 11, a ring-shaped second structure 12, a plurality of third structures 13 serving as beams, and a plurality of strain sensors 14.

[0034] The first structure 11, the second structure 12, and the third structure 13 are elastic bodies made of metal, such as stainless steel. However, they are not limited to stainless steel and other metals can also be used.

[0035] like Figure 2 As shown, the first structure 11 has a first outer diameter OD1 and a first inner diameter ID1 smaller than the first outer diameter OD1, and the second structure 12 has a second outer diameter OD2 smaller than the first inner diameter ID1 and a second inner diameter ID2 smaller than the second outer diameter OD2 (OD1>ID1>OD2>ID2).

[0036] The second structure 12 is concentric with respect to the first structure 11, and along the axial direction passing through the center of the first structure 11, it moves away from the first structure 11 by a predetermined interval, for example, only a distance L. Figure 3 (As shown) and configuration.

[0037] like Figure 1 As shown, the axial thickness T1 of the first structure 11 is equal to the axial thickness T2 of the second structure 12 (T1=T2). However, it is not limited to this, the thickness T1 of the first structure 11 and the thickness T2 of the second structure 12 may also be different.

[0038] Multiple third structures 13 are arranged radially relative to the first structure 11 and the second structure 12, connecting the axially separated first structure 11 and second structure 12. Details regarding the third structures 13 will be described later.

[0039] like Figure 2 As shown, a plurality of strain sensors 14 are arranged at different positions from the third structure 13, between the first structure 11 and the second structure 12, in a direction orthogonal to the axis. In the first embodiment, the number of strain sensors 14 is, for example, eight, but is not limited thereto, and may also be four or two.

[0040] Each strain sensor 14 includes a strain gauge 14a made of an elastomer, such as a metal, and a plurality of strain gauges 14b configured on the strain gauge 14a via an insulating membrane (not shown).

[0041] One end of the strain gauge 14a is disposed on the first structure 11, and the other end is disposed on the second structure 12. One end of the strain gauge 14a is fixed to the first structure 11 by a fixing member 15a disposed on the first structure 11 and a screw 15b inserted into and screwed into the fixing member 15a from the back of the first structure 11. The other end of the strain gauge 14a is fixed to the second structure 12 by a fixing member 16a disposed on the second structure 12 and a screw 16b inserted into and screwed into the fixing member 16a from the back of the second structure 12.

[0042] Multiple strain sensors 14, for example, forming multiple bridge circuits (not shown), detect torque through these bridge circuits.

[0043] in addition, Figure 1 , Figure 4 , Figure 5 The structures of strain sensor 14 and fixed strain sensor 14 are omitted in the text. Furthermore, this embodiment is not limited to torque sensors, but can also be applied to force sensors that detect torque and multiple torques.

[0044] like Figure 1 , Figure 3 , Figure 4 As shown, the first structure 11 includes a first surface (hereinafter also referred to as surface) 11a, a second surface (hereinafter also referred to as back surface) 11b parallel to the first surface 11a, a first outer surface (hereinafter also referred to as outer surface) 11c connecting the outer side of the first surface 11a and the outer side of the second surface 11b, and a first inner surface (hereinafter also referred to as inner surface) 11d connecting the inner side of the first surface 11a and the inner side of the second surface 11b.

[0045] The second structure 12 includes an annular third surface (hereinafter also referred to as surface) 12a, a fourth surface 12b (hereinafter also referred to as back surface) parallel to the third surface 12a, a second outer surface (hereinafter also referred to as outer surface) 12c connecting the outer side of the third surface 12a and the outer side of the fourth surface 12b, and a second inner surface (hereinafter also referred to as inner surface) 12d connecting the inner side of the third surface 12a and the inner side of the fourth surface 12b.

[0046] The first structure 11 includes a plurality of holes 11e and 11f extending from the surface 11a to the back surface 11b, and the second structure 12 includes a plurality of holes 12e and 12f extending from the surface 12a to the back surface 12b.

[0047] An unillustrated bolt is inserted into hole 11e to secure the first structure 11 to, for example, a robotic arm (not shown), and an unillustrated bolt is inserted into hole 12e to secure the second structure 12 to, for example, a reducer connected to a motor (not shown).

[0048] Insert a screw 15b into hole 11f and tighten it with the aforementioned fixing member 15a; insert a screw 16b into hole 12f and tighten it with the aforementioned fixing member 16a.

[0049] Multiple third structures 13 connect the axially separated first structure 11 and second structure 12. Therefore, the axial thickness T3 of the third structure 13 is greater than the thickness T1 of the first structure 11 and the thickness T2 of the second structure 12 (T3 > T1, T2). Furthermore, the third structure 13 has a width W in the axial direction. The width W of the third structure 13 in the axial direction is determined, for example, based on the maximum stress relative to the torque.

[0050] like Figures 1 to 5 As shown, the strain sensor 14 is disposed between a pair of third structures 13. The pair of third structures 13 are connected to at least the surface 11a of the first structure 11 and at least the back surface 12b of the second structure 12.

[0051] like Figure 5 As shown, a first recess 11g, a second recess 12g, a third recess 11h, and a fourth recess 12h are provided in the portion corresponding to a pair of third structures 13 that house the strain sensor 14. The first recess 11g is positioned above the surface of the first structure 11, and the second recess 12g is positioned below the surface of the second structure 12 and corresponding to the first recess 11g, i.e., corresponding in the direction perpendicular to the axis. The bottom surfaces of the first recess 11g and the second recess 12g are at the same horizontal level. Specifically, the bottom surface of the first recess 11g is higher than the surface of the first structure 11, and the bottom surface of the second recess 12g is lower than the back surface 12b of the second structure 12.

[0052] The third recess 11h is disposed on the back side of the first structure 11 at a position corresponding to the first recess 11g, and the fourth recess 12h is disposed on the back side of the second structure 12 at a position corresponding to the third recess 11h. The bottom surfaces of the third recess 11h and the fourth recess 12h are at the same horizontal position. Specifically, the bottom surface of the third recess 11h is higher than the surface 11a of the first structure 11, and the bottom surface of the fourth recess 12h is lower than the back side 12b of the second structure 12.

[0053] In other words, the portions provided with the first recess 11g to the fourth recess 12h have the same thickness T3 as the third structure 13, and the bottom surfaces of the first recess 11g and the second recess 12g are positioned at a position higher in the axial direction than the surface 11a of the first structure 11.

[0054] One end of the strain gauge 14a constituting the strain sensor 14 is placed on the bottom surface of the first recess 11g, and the other end of the strain gauge 14a is placed on the bottom surface of the second recess 12g. In addition, a fixing member 15a is placed on the bottom surface of the first recess 11g, and a fixing member 16a is placed on the bottom surface of the second recess 12g.

[0055] The aforementioned hole 11f extends from the first recess 11g to the third recess 11h, and the hole 12f extends from the second recess 12g to the fourth recess 12h.

[0056] (The composition of the third structure) Figure 6 This is a diagram showing the third structure 13 after it has been removed. The third structure 13 is connected to the first structure 11 and the second structure 12, which are arranged in a axially separated manner with different diameters. Therefore, the side surface of the third structure 13 is approximately parallelogram-shaped and has a thickness T3 (T3≥L) greater than or equal to the axial distance L between the first structure 11 and the second structure 12.

[0057] Furthermore, the third structure 13 has a length L2 that is greater than the distance L1 between the first structure 11 and the second structure 12 in a direction orthogonal to the axis. In other words, the third structure 13 has a length L2 that is greater than the first inner diameter ID1 of the first structure 11 (e.g., ...). Figure 2 (as shown) and the second outer diameter OD2 of the second structure 12 (as shown) Figure 2 The distance L1 is half the length L2 of the difference between the two (as shown).

[0058] The third structure 13 includes a first portion 13a and a second portion 13b orthogonal to an axis passing through the centers of the first structure 11 and the second structure 12, and a third portion 13c and a fourth portion 13d inclined relative to the axis. Furthermore, the third structure 13 includes a first step portion 13e between the first portion 13a and the third portion 13c, and a second step portion 13f between the second portion 13b and the fourth portion 13d.

[0059] The first part 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and the first stepped part 13e is connected to the outer surface 12c. The second part 13b of the third structure 13 is connected to the surface 11a of the first structure 11, and the second stepped part 13f is connected to the inner surface 11d of the first structure 11. The angle between the fourth part 13d of the third structure 13 and the surface 11a of the first structure 11 is θ1, and the angle between the third part 13c of the third structure 13 and the back surface 12b of the second structure 12 is also θ1 (not shown).

[0060] In the first portion 13a of the third structure 13, the portion connected to the outer surface 12c of the second structure 12 includes a recess 13g recessed along the axial direction, and includes a protrusion 13h on the side of the first structure 11 that serves as the recess 13g. However, it is not limited to this; the recess 13g may be omitted, or it may be a flat state parallel to the surface 12a of the second structure 12.

[0061] Reference Figure 6 The function of the third structure 13 will be explained.

[0062] The third structure 13 of the first embodiment has the function of suppressing the deformation of torques Mx and My in directions other than torque.

[0063] Specifically, when a torque Mz in the direction of torque is applied between the first structure 11 and the second structure 12, the first structure 11 and the second structure 12 are displaced relative to each other in the direction about the axis. On the other hand, when a torque Mx and / or My in a direction other than torque is applied between the first structure 11 and the second structure 12, the first structure 11 and the second structure 12 are displaced in a manner that is inclined relative to the axis.

[0064] In contrast, the third structure 13 has a length L2, which is greater than the distance L1 between the first structure 11 and the second structure 12 in the direction orthogonal to the axis. The third structure 13 has a thickness T3, which is greater than or equal to the axial distance L between the first structure 11 and the second structure 12. Therefore, for a torque Mz in the torque direction, the third structure 13 can easily displace the first structure 11 and the second structure 12 in the direction of arrow A or B shown in the figure. For torques Mx and My other than torque, it can suppress the displacement of the first structure 11 and the second structure 12 in the direction of arrow C or D shown in the figure. That is, when a torque Mz in the torque direction is applied to the torque sensor 10, deformation caused by torques Mx and My in directions other than torque can be suppressed.

[0065] Furthermore, the first portion 13a of the third structure 13 correspondingly includes a recess 13g between the first structure 11 and the second structure 12, including a protrusion 13h on the side of the first structure 11 that serves as the recess 13g. By including this protrusion 13h, the third structure 13 can further suppress the displacement of the first structure 11 and the second structure 12 in the direction of arrow C or D as illustrated, for torques Mx and My other than torque.

[0066] (The first variation of the third structure) The angle between the fourth part 13d of the third structure 13 and the surface of the first structure 11 is not limited to θ1.

[0067] Figure 7 A first variation of the third structure 13 is shown, wherein the angle between the fourth portion 13d of the third structure 13 and the surface 11a of the first structure 11 is an angle θ2 (θ1 < θ2) greater than θ1. In other words, the lengths of the first portion 13a and the second portion 13b of the third structure 13 are greater than... Figure 6 The lengths of the first part 13a and the second part 13b of the third structure 13 shown are long.

[0068] The third structure 13 involved in the first variation and Figure 6 The volume of the third structure 13 shown is increased. Therefore, although the mass of the torque sensor 10, including the weight of the third structure 13, increases, the rigidity of the third structure 13 is improved, thus increasing the rigidity relative to the torques Mx and My in each direction.

[0069] Furthermore, the first portion 13a of the third structure 13 includes a recess 13g between the first structure 11 and the second structure 12, and includes a protrusion 13h on the side of the first structure 11 that serves as the recess 13g. By including this protrusion 13h, the third structure 13 can further suppress the displacement of the first structure 11 and the second structure 12 in the direction of arrow C or D as illustrated, relative to torques Mx and My other than torque.

[0070] Figure 8 The angle between the surface of the first structure 11 and the fourth part 13d of the third structure 13 is shown, along with the relationship between the displacement, mass, and stress in the direction of the torques Mx and My. Figure 8 In the diagram, curve A represents the displacement for torques Mx and My, curve B represents the mass, curve C represents the stress in the direction of torque, and curve D represents an approximation of curve C.

[0071] As shown by curve D, the stress when torque is applied to the torque sensor 10 decreases in the range of angles from 40° to 60°, and is lowest in the range of angles from 45° to 50°. Therefore, the required angle range for detecting torque is 40° to 60°, preferably 45° to 50°.

[0072] On the other hand, as shown by curve A, the displacement with respect to moments Mx and My is minimal when the angle is above 45°. That is, it can be seen that the stiffness relative to moments Mx and My is high within the range of angles above 45° and below 90°. In other words, the longer the length of the first part 13a of the third structure 13, the higher the stiffness relative to moments Mx and My. However, as shown by curve B, the mass of the third structure 13 increases with increasing angle.

[0073] Therefore, in the first embodiment, taking into account the detection of torque and the rigidity relative to the moment, the angle between the surface 11a of the first structure 11 and the second part 13b of the third structure 13 is preferably in the range of 40° to 60°, and more preferably in the range of 45° to 50°.

[0074] (Effects of the first implementation method) According to the first embodiment, the second structure 12 has an outer diameter smaller than the inner diameter of the first structure 11, and is axially separated from the first structure 11. A plurality of third structures 13 connecting the first structure 11 and the second structure 12 have a length L2, which is larger than the distance L1 between the first structure 11 and the second structure 12 in a direction orthogonal to the axis, and also have a thickness T3, which is greater than or equal to the axial distance L between the first structure 11 and the second structure 12. Therefore, deformation caused by torques Mx and My in directions other than torque can be suppressed, and a high-rigidity torque sensor can be constructed.

[0075] Furthermore, the first portion 13a of the third structure 13 is connected to at least the fourth surface 12d of the second structure 12, and the second portion 13b of the third structure 13 is set as at least the first surface 11a of the first structure 11. Therefore, the rigidity of the torque sensor 10 can be maintained, and the thicknesses T1 and T2 of the first structure 11 and the second structure 12 can be reduced. Therefore, it is possible to achieve a thinner (miniaturized) and lighter torque sensor 10.

[0076] Furthermore, based on the configuration of the third structure 13, when a torque Mz in the torque direction is applied to the torque sensor 10, deformation caused by torques Mx and My in directions other than torque can be suppressed. Therefore, torque can be accurately detected while preventing interference from other axes.

[0077] Furthermore, the angle between the surface 11a of the first structure 11 and the fourth portion 13d of the third structure 13 is set to a range of 40° to 60°. Therefore, even with a reduction in the thickness of the first structure 11 and the second structure 12 to achieve weight reduction, the rigidity in the torque Mx and My directions can be improved, and the increase in the combined axial thickness (height) of the first structure 11, the second structure 12, and the third structure 13 can be suppressed. Therefore, the torque sensor 10 of the first embodiment can provide a torque sensor that maintains torque detection accuracy and is highly rigid, thin, and lightweight.

[0078] Figure 9A This illustrates the application of the torque sensor 10 of the first embodiment to the robotic arm 31. Figure 9B The example shown illustrates the application of a torque sensor 32, as illustrated in Patent Document 1, to a robotic arm 31.

[0079] When the joint rigidity of a robotic arm is low, it becomes difficult to determine the position of the arm's tip due to inertia when the arm is driven to a designated location. Therefore, the joints of a robotic arm, including torque sensors, require high rigidity. Furthermore, the inertia when the robotic arm stops is easily suppressed when the joints, including torque sensors, are relatively lightweight. And, as... Figure 9A As shown, the axial height H of the torque sensor 10 is compared to... Figure 9BWhen the axial height H of the torque sensor 32 shown is short, the torque other than the torque itself is smaller. Therefore, the influence of interference from other axes is smaller, enabling higher precision control. In other words, when the load applied to the robot arm 10 is equal, the larger the axial height H of the torque sensor 10, the larger the torque other than the torque applied to the torque sensor 10.

[0080] Figure 10 The axial height of the torque sensor and the displacement in the axial (z-axis) direction when applied torques Mx and My are shown. The torque sensor 10 of the first embodiment has a slightly larger height H compared to the structure in Patent Document 2, and half the height H compared to the structure in Patent Document 1, but significantly reduces the displacement in the axial (z-axis) direction when applied torques Mx and My compared to the structure in Patent Document 2. That is, the torque sensor 10 of the first embodiment can improve rigidity for torques Mx and My while maintaining a thin profile. Therefore, it is possible to prevent interference from other axes and improve the accuracy of torque detection.

[0081] Figure 10 The first embodiment is compared with Patent Documents 1 and 2 to illustrate the effect, but the first embodiment can also achieve the same effect as Patent Documents 1 and 2 relative to Patent Documents 3 and 4.

[0082] (A variation of the third structure) Figure 11 A second variation of the third structure 13 is shown. In the second variation, the third structure 13 has a first step portion 13e between the first portion 13a and the fourth portion 13d, and a second step portion 13f between the second portion 13b and the third portion 13c.

[0083] The first part 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and the first stepped part 13e is connected to the outer surface 12c of the second structure 12. The second part 13b of the third structure 13 is connected to the surface 11a of the first structure 12, and the second stepped part 13f is connected to the inner surface 11d of the first structure 11. The angle between the fourth part 13d of the third structure 13 and the surface 11a of the first structure 11 is θ.

[0084] According to the second modification, the same effect as the first embodiment can be obtained. Moreover, compared with the first embodiment, the volume of the third structure 13 can be reduced, thereby making the torque sensor 10 even lighter.

[0085] Figure 12A third variation of the third structure 13 is shown. In this third variation, the side profile of the third structure 13 is a parallelogram. The entire first portion 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and the entire second portion 13b of the third structure 13 is connected to the surface 11a of the first structure 11. The third portion 13c and the fourth portion 13d, as inclined portions of the third structure 13, are not connected to either the first structure 11 or the second structure 12.

[0086] The third modification achieves the same effect as the first embodiment. Furthermore, compared to the second modification, the volume of the third structure 13 can be further reduced, thus making the torque sensor 10 even lighter.

[0087] Furthermore, in the second and third modifications, the second structure 12 can form concentric circles that partially overlap with the first structure 11 in the radial direction within the range of the angle θ formed by the fourth portion 13d of the third structure 13 and the surface 11a of the first structure 11. However, by forming recesses in the first structure 11 and the second structure 12 respectively, the strain sensor 14 can be disposed between the first structure 11 and the second structure 12.

[0088] Furthermore, in the second and third modifications, the width W of the third structure 13 can also vary depending on the maximum stress relative to the required torque and moment.

[0089] Figure 13 A fourth variation of the third structure 13 is shown. In this fourth variation, the side profile of the third structure 13 is not a parallelogram, but a rectangle. Therefore, the third part 13c and the fourth part 13d intersect at right angles with respect to the first part 13a and the second part 13b, and the angle between the fourth part 13d and the surface 11a of the first structure 11 is 90°.

[0090] A portion of the first part 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and a portion of the second part 13b is connected to the surface 11a of the first structure 11. Figure 8 As shown by curve A, the rectangular third structure 13 has a relatively high rigidity relative to the torques Mx and My.

[0091] Figure 14 This represents a fifth variation of the third structure 13. In this fifth variation, a portion of the third structure 13 shown in the fourth variation is chamfered and removed, resulting in a parallelogram-shaped side profile. Therefore, the third structure 13 comprises an inclined third portion 13c and a fourth portion 13d.

[0092] A portion of the first part 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and a portion of the second part 13b is connected to the surface 11a of the first structure 11. The third structure 13 of the fifth modification is lighter than the third structure 13 shown in the fourth modification.

[0093] Figure 15 A sixth variation of the third structure 13 is shown. In this sixth variation, the third structure 13 is generally rectangular, and the angle between the fourth portion 13d and the surface 11a of the first structure 11 is 90°. The third structure 13 includes a first step portion 13e between the first portion 13a and the third portion 13c, and a second step portion 13f between the second portion 13b and the fourth portion 13d.

[0094] A portion of the first part 13a of the third structure 13 is connected to the back surface 12b of the second structure 12, and the first stepped portion 13e is connected to the outer surface 12c of the second structure 12. Therefore, the remaining portion of the first part 13a is consistent with the surface of the second structure 12. A portion of the second part 13b of the third structure 13 is connected to the surface 11a of the second structure 12, and the second stepped portion 13f is connected to the inner surface 11d of the first structure 11. Therefore, the remaining portion of the second part 13b is consistent with the back surface of the first structure 11.

[0095] As will be described later, the third structure 13 of the sixth modification example has a reduced maximum stress when applied torques Mx and My compared to the third structure 13 of the fourth modification example, which can improve the rigidity in the axial (z-axis) direction.

[0096] Figure 16 A seventh variation of the third structure 13 is shown. In this seventh variation, a portion of the third structure 13 shown in the sixth variation is removed by chamfering. Therefore, the third structure 13 includes an inclined third portion 13c and a fourth portion 13d. That is, the angle formed between the fourth portion 13d and the surface 11a of the first structure 11 is less than 90°. The third structure 13 of the seventh variation is the same as the third structure 13 of the first embodiment, but is shown for ease of explanation. The seventh variation achieves a lighter weight compared to the sixth variation.

[0097] Here, Figure 11 The shape of the third structure 13 in the second modified example shown is called (outer-outer-inclined). Figure 12 The shape of the third structure 13 in the third variation shown is called (inner-inner-inclined), and it will... Figure 13 The shape of the third structure 13 in the fourth variation example shown is called (inner-inner-quadrilateral). Figure 14The shape of the third structure 13 in the fifth variation shown is called (inner-inner-bevel), which will... Figure 15 The shape of the third structure 13 in the sixth variation shown is called (outer-outer-quadrilateral). Figure 16 The shape of the third structure 13 in the seventh variation shown is called (outer-outer-bevel).

[0098] Figure 17 It shows the Figures 11 to 16 The relationship between the maximum stress and the displacement in the axial (z-axis) direction when applied to the third structure 13 in the second to seventh modifications is shown. The smaller the value of the displacement in the axial (z-axis) direction, the higher the rigidity. In addition, the width W and length L2 of the third structure 13 in each modification are the same.

[0099] like Figure 17 As shown in E, it can be seen that if... Figure 12 Taking the third structure 13 (inner-inner-inclined) of the third variant shown as a reference, then Figure 11 The third structure 13 (outer-outer-inclined) of the second modified example shown can reduce the maximum stress and has high rigidity compared with the third modified example.

[0100] Furthermore, in the case of Figure 11 The maximum stress in the second deformation example (outer-outer-inclined) shown is assumed to be the same as that in the second deformation example (outer-outer-inclined). Figure 12 Under the same maximum stress, the third structure 13 of the second modification (outer-outer-inclined) has higher rigidity than the third structure 13 of the third modification (inner-inner-inclined). Therefore, the thickness and axial spacing between the first structure 11 and the second structure 12 can be reduced. Thus, miniaturization and thinning of the torque sensor 10 can be achieved.

[0101] In addition, such as Figure 17 As shown in F, it can be seen that Figure 13 The fourth variation shown (inner-inner-quadrilateral), and Figure 14 The third structure 13 of the fifth variation (inner-inner-bevel) shown is... Figure 12 In the third modified example (inner-inner-inclined), the rigidity of the third structure in the axial (z-axis) direction is the same when a torque is applied, and the maximum stress is reduced. Therefore, compared with the third modified example (inner-inner-inclined), the fourth modified example (inner-inner-quadrilateral) and the fifth modified example (inner-inner-chamfered) can reduce the thickness and axial spacing between the first structure 11 and the second structure 12. Therefore, miniaturization and thinning of the torque sensor 10 can be achieved.

[0102] Furthermore, such as Figure 17 As shown in G, it can be seen that Figure 15The sixth variation shown (outer-outer-quadrilateral), and Figure 16 The third structure 13 of the seventh variation (outer-outer-bevel) shown is... Figure 11 Compared to the third structure in the second modified example (outer-outer-inclined) shown, the rigidity in the axial (z-axis) direction when a torque is applied is higher, and the maximum stress is reduced. Therefore, compared to the second modified example (outer-outer-inclined), the sixth modified example (outer-outer-quadrilateral) and the seventh modified example (outer-outer-chamfered) can reduce the thickness and axial spacing between the first structure 11 and the second structure 12. Therefore, the torque sensor 10 can be further miniaturized and thinned.

[0103] (Second Implementation) Figure 18 , Figure 19 A second embodiment of the torque sensor is shown. In the first embodiment, the plurality of third structures 13 are arranged independently, except for a pair of third structures 13 disposed on both sides of the strain sensor 14.

[0104] On the other hand, in the second embodiment, all the third structures 13, including a pair of third structures 13 disposed on both sides of the strain sensor 14, are connected on the surface 11a of the first structure 11. That is, the surface 11a of the first structure 11 includes an annular first connecting portion 11i, and the plurality of third structures 13 are connected through the first connecting portion 11i. The thickness of the first connecting portion 11i along the axial direction of the first structure 11 is equal to the distance L12 from the surface 11a of the first structure 11 to the surface 12a of the second structure 12, and the width W12 in the direction orthogonal to the axis is approximately 1 / 8 of the width W1 of the first structure 11. However, the thickness and width of the first connecting portion 11i are not limited to this.

[0105] According to the second embodiment, a plurality of third structures 13 are connected by an annular first connecting portion 11i provided on the surface 11a of the first structure 11. This improves the rigidity of the plurality of third structures 13 and the first structure 11. Therefore, it is possible to suppress the increase in the thickness of the torque sensor 10, increase the maximum stress relative to torque and moment, and improve the torque sensor 10's accuracy in detecting torque.

[0106] (Third implementation method) Figure 20 , Figure 21 A third embodiment is shown.

[0107] In the second embodiment, a plurality of third structures 13 are connected to the surface 11a of the first structure 11 via a first connecting portion 11i.

[0108] On the other hand, in the third embodiment, a plurality of third structures 13 are connected to the back surface 12b of the second structure 12 via a second connecting portion 12i. That is, the back surface 12b of the second structure 12 includes an annular second connecting portion 12i, and a plurality of third structures 13 are connected via the second connecting portion 12i. The thickness of the second connecting portion 12i along the axial direction of the second structure 12 is equal to the distance L12 from the back surface 12b of the second structure 12 to the back surface 11b of the first structure 11, and the width W12 in the direction orthogonal to the axis is approximately 1 / 8 of the width W2 of the second structure 12. However, the thickness and width of the second connecting portion 12i are not limited thereto.

[0109] According to the third embodiment, a plurality of third structures 13 are connected by an annular second connecting portion 12i provided on the back surface 12b of the second structure 12. This improves the rigidity of the plurality of third structures 13 and the second structure 12. Therefore, it suppresses the increase in the thickness of the torque sensor 10, increases the maximum stress relative to torque and moment, and improves the torque sensor 10's accuracy in detecting torque.

[0110] (Fourth Implementation) Figure 22 A fourth embodiment is shown. The fourth embodiment is a combination of the second and third embodiments.

[0111] In the fourth embodiment, the plurality of third structures 13 are connected by an annular first connecting portion 11i provided on the surface 11a of the first structure 11 and an annular second connecting portion 12i provided on the back surface 12b of the second structure 12. This improves the rigidity of the plurality of third structures 13, the first structure 11, and the second structure 12. Therefore, it is possible to suppress the increase in the thickness of the torque sensor 10, further increase the maximum stress relative to torque and moment, and improve the torque sensor 10's accuracy in detecting torque.

[0112] Furthermore, the present invention is not limited to the embodiments described above. During implementation, the constituent elements can be modified and made more specific without departing from its essence. Moreover, various inventions can be formed by appropriately combining multiple constituent elements disclosed in the above embodiments. For example, several constituent elements can be deleted from all the constituent elements shown in the embodiments. Furthermore, constituent elements from different embodiments can be appropriately combined.

Claims

1. A torque sensor, comprising: A ring-shaped first structure having a first outer diameter and a first inner diameter; A ring-shaped second structure, which is separately disposed from the first structure on the axis of the first structure, has a second outer diameter and a second inner diameter that are smaller than the first inner diameter; A plurality of third structures are connected between the first structure and the second structure, and have at least a thickness greater than the axial distance between the first structure and the second structure, and a width in a direction orthogonal to the axis that is wider than the distance between the first structure and the second structure. as well as Multiple strain sensors are connected between the first structure and the second structure and are arranged perpendicularly to the axis.

2. The torque sensor according to claim 1, wherein, The third structure is a quadrilateral comprising at least a first part and a second part orthogonal to the axis, and a third part and a fourth part having an angle less than a right angle with the axis, wherein at least the first part is connected to the second structure, and at least the second part is connected to the first structure.

3. The torque sensor according to claim 2, wherein, The angle between the fourth part of the third structure and the first structure is in the range of 40° to 60°.

4. The torque sensor according to claim 2, wherein, The angle between the fourth part of the third structure and the first structure is between 45° and 50°.

5. The torque sensor according to claim 2, wherein, The first portion of the third structure includes a recess corresponding to the first structure and the second structure, and includes a protrusion as a side surface of the first structure side of the recess.

6. The torque sensor according to claim 2, wherein, The first structure has an annular first surface, an annular second surface parallel to the first surface, a first outer surface connecting the outer sides of the first surface and the second surface, and a first inner surface connecting the inner sides of the first surface and the second surface. The second structure has an annular third surface, an annular fourth surface parallel to the third surface, a second outer surface connecting the outer sides of the third surface and the fourth surface, and a second inner surface connecting the inner sides of the third surface and the fourth surface.

7. The torque sensor according to claim 6, wherein, The first portion of the plurality of third structures is connected to at least the fourth surface of the second structure, and the second portion of the plurality of third structures is connected to at least the first surface of the first structure.

8. The torque sensor according to claim 6, wherein, The plurality of third structures include a first step portion between the first portion and the third portion, and a second step portion between the second portion and the fourth portion. The first step portion is connected to the second outer side surface of the second structure, and the second step portion is connected to the first inner side surface of the first structure.

9. The torque sensor according to claim 6, wherein, The third structure includes a first step portion between the first part and the fourth part, and a second step portion between the second part and the third part. The first part is connected to the fourth surface of the second structure, the first step portion is connected to the second outer surface of the second structure, the second part is connected to the first surface of the first structure, and the second step portion is connected to the first inner surface of the first structure. The angle between the fourth part and the first surface of the first structure is less than a right angle.

10. The torque sensor according to claim 6, wherein, The side profile of the third structure is a parallelogram. The first part is connected to the fourth surface of the second structure, and the second part is connected to the first surface of the first structure.

11. The torque sensor according to claim 6, wherein, The side of the third structure is rectangular, a portion of the first part is connected to the fourth side of the second structure, and a portion of the second part is connected to the first side of the first structure.

12. The torque sensor according to claim 6, wherein, The side profile of the third structure is a parallelogram. A portion of the first part is connected to the fourth surface of the second structure, and a portion of the second part is connected to the first surface of the first structure.

13. The torque sensor according to claim 6, wherein, The third structure includes a first step portion between the first part and the third part, and a second step portion between the second part and the fourth part. A portion of the first part is connected to the fourth surface of the second structure. The first step portion is connected to the second outer surface of the second structure. A portion of the second part is connected to the first surface of the first structure. The second step portion is connected to the first inner surface of the first structure. The angle between the fourth part and the first surface of the first structure is a right angle.

14. The torque sensor according to claim 6, wherein, The third structure includes a first step portion between the first part and the third part, and a second step portion between the second part and the fourth part. A portion of the first part is connected to the fourth surface of the second structure. The first step portion is connected to the second outer surface of the second structure. A portion of the second part is connected to the first surface of the first structure. The second step portion is connected to the first inner surface of the first structure. The angle between the fourth part and the first surface of the first structure is less than a right angle.

15. The torque sensor according to claim 1, wherein, The first structure has a first recess at one end where the strain sensor is disposed, and the second structure has a second recess at the other end where the strain sensor is disposed. The bottom of the second recess in the direction intersecting the axis of the first structure is at the same position as the bottom of the first recess in the direction intersecting the axis of the first structure.

16. The torque sensor according to claim 6, further comprising an annular first connecting portion connecting the plurality of third structures on the first surface of the first structure.

17. The torque sensor according to claim 6, further comprising an annular second connecting portion connecting the plurality of third structures on the fourth surface of the second structure.

18. The torque sensor according to claim 6, further comprising an annular first connecting portion connecting the plurality of third structures on the first surface of the first structure, and an annular second connecting portion connecting the plurality of third structures on the fourth surface of the second structure.

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